linux-kernel - Re: [PATCH 02/10] nohz: Kick full dynticks timer targets with an empty IPI

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140719135415.GB16673@localhost.localdomain>
Date:	Sat, 19 Jul 2014 15:54:17 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Viresh Kumar <viresh.kumar@...aro.org>
Subject: Re: [PATCH 02/10] nohz: Kick full dynticks timer targets with an
 empty IPI

On Sat, Jul 19, 2014 at 03:47:41PM +0200, Peter Zijlstra wrote:
> On Sat, Jul 19, 2014 at 03:18:47PM +0200, Frederic Weisbecker wrote:
> > On Sat, Jul 19, 2014 at 09:19:51AM +0200, Peter Zijlstra wrote:
> > > On Sat, Jul 19, 2014 at 02:44:13AM +0200, Frederic Weisbecker wrote:
> > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > > > index 7f3063c..f3e48b8 100644
> > > > --- a/kernel/sched/core.c
> > > > +++ b/kernel/sched/core.c
> > > > @@ -693,7 +693,7 @@ static bool wake_up_full_nohz_cpu(int cpu)
> > > >  	if (tick_nohz_full_cpu(cpu)) {
> > > >  		if (cpu != smp_processor_id() ||
> > > >  		    tick_nohz_tick_stopped())
> > > > -			tick_nohz_full_kick_cpu(cpu);
> > > > +			irq_work_void_on(cpu);
> > > 
> > > So no, while the previous function name was descriptive, the new one
> > > leave one wondering.
> > 
> > Yeah, I suppose I can wrap that to some new function: tick_nohz_full_reschedule_cpu()
> > for example (although that looks a bit like a sched thing).
> > 
> > That said I plan to gather tick stop and tick restart in the same place, in the
> > end of the interrupt. So in the end we'll have only one tick_nohz_full_kick_cpu()
> > for all kick uses, and this will just wrapp to irq_work_void_on().
> 
> So there's already kick_all_cpus_sync() in kernel/smp.c, I would suggest
> implementing your irq_work_void_on() as kick_cpu() right next to it.

Good point!

> 
> And yes, I would suggest also keeping tick_nohz_full_kick_cpu() as a
> 'pointless' wrapper purely for 'documentation' value.

Ok, granted!

Thanks!
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/